Horizontal hydraulic broaching machine



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K. C. MONROE HORIZONTAL HYDRAULIC BROACHING MACHINE- Filed June 2l, 1940 l L I I I F H IP II HO bh. 2\. H hliIHsuH|||| ami I www QIJIL Nov. 24, 1942.v

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HOBIZONTALHYDRAULC BROACBING MAHINE Kenneth C. Monroe, Hudson, assigner to The Lapointe Machine Tool Company, Bud-ron, Mass., a corporation oi' Maine Application June 21, 1940, Serial No. Sdli@ 1': claim. (ci. son-3s) This invention relates to breaching machines oi the horizontal type which are :provided with hydraulic operating mechanism.

llt is the general object of my present invention to provide a horizontal hydraulic broaching machine in which the diierent parts of the machine e so controlled or interlocked that unintended, 'sa f or dangerous operation of the machine is substantially impossible.

To the attainment of this object, one feature oi the invention relates to a system of electrical controls so designed that the machine will stop ii the various control circuits are not closed and opened in predetermined order, and will also stop on any failure of current in the control circuits.

, I have also provided control devices which may be set to stop the machine after each broaching stroke and each return stroke, or only after each v return stroke, as desired.

Another feature oi' my invention relates tc the provision oi mechanism for automatically holding the machine in operation after a working or re- 1 stroke has been started and until the stroke has been completed, or, alternately, for stopping the machine at any point in a stroke whenever the cut or return switch is opened.

also provide improved hydraulic devices for handling excess oil delivered from the main' 'cylinder during the high speed return stroke.

My invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claims. l

A preferred form of the invention is shown .in the drawings, in which Fig. i is a diagrammatic plan view of the r`perating parts of my improved broaching machine, together with the hydraulic connections and electrical control devices. all shown in idle or neutral position:

Fig'. 2 is a view similar to Fig. l but showing various parts inthe positions assumed during the cutting stroke; and

Fig. 3 is a view similar to Fig. l but showing Vthe rts in the position assumed during the return stroire. l

Referring .to the drawings, I have shown the essential parts of a horizontal hydraulic broaching machine comprising a main cylinder it in l which a piston ii is reciprocated. The piston il is connected by a piston rod i2 to a broaching or puller head it, in which a broach B may be detechably secured. The piston rod i2 has a rela tively small axial bore or recess I5, and the cylin and slidable in the passage it.

'I'he left-hand end of the cylinder it, as viewed in Fig. l, is connected by a pipe it to one of the discharge openings of a variable discharge rey versible main-pump P. 'Ihe other discharge opening of the pump P is similarly connected by a pipe i9 and passage 20 to a recess or chamber 2i in the right-hand end of the cylinder it. This recess or chamber 2i is connected by a port 22 to the inside of the xed tubular rod it, and by a port 23 to the right-hand end oi the cylinder It.

Passages 25 and 28 connect the recess 2i and the left-hand end of the cylinder it respectively to the cylinder 3d of a differential valve V, which is mounted above the main cylinder Ill and within a. storage tank or reservoir T to which surplus oil may be delivered or from which oil may be withdrawn by the pumps.

A check valve 32 in the recess or chamber 2i prevents ow of oil upward from the passage til to the port 23 or to the passage 25, but permits free flow in the opposite direction.

The pump P is provided with suitable devices such as a pinion 35 and rack et, by which the pump P may be set to discharge at any desired rate and in either direction. shown as connected by a piston rod 31 to a piston 38 slidable in a pump control cylinder 40 and normally spring-centered therein by centering devices of any usual construction.

'I'he ends of the cylinder t@ are connected by pipes di and d2 to a solenoid-operated control valve W which is normally spring-centered in neutral position but which may be displaced to the position shown in Fig. 2 if the solenoid dt is energized, or to the position shown in Fig. 3 if the solenoid d5 is energized.

Oil under pressure for actuating the -pump con- 1 trol cylinder lili is supplied from a continuously operating auxiliary pump P', which receives a supply of oil through a pipe 4E from the tank T and which delivers oil under pressure through a pipe 48, relief valve i353, needle valve and pipe 5| lto the solenoid operated valve Vi.l The valve W also has a discharge pipe 52 which discharges oil at atmospheric pressure to the tank T, and to which pipe is connected the discharge pipe 53 of the relief valve t9.

The pump P is preferably provided with a bypass circuit 55 having a normally open valve V3 controlled by a solenoid 58. When the machine is operating, either on a cut or return stroke, the solenoid @t is energized and the valve W n closed.

'I'he rack 36 is 2 and 3,- out when the mochine velve V3 opens end the pipe S55 then ovlq or shunt circuit lor any smell oniount of oil which may be discharged hy the europ P the pump control cylinder should not set the hump in exactly neutral position. This ley-pass thus prevents any creeping oi the piston ll Torosching heed lf3 in either direction while t schine is idle.

The .nerentinl vulve V includes c. piston l@ slidehle in the cylinder 3@ and having spaced piston elements il end l2, with an interposed cosce The/piston valve l@ ls provided with piston rod extensions lo and l@ at its two ends, which extensions are slidcble in asini openings or nsaees "il and ld in the heads o the valve V.

il@ opens into the cylinder il@ snel is ed with on inwardly opening 'vent or checl:

"the passages sind previously cieonen `lntc annuler ports end in the e cylinder e ed. the colt connects l delve i 'cines ll and 32 controlled hy the solenoid1 o cted valve V2 ere connected by lorsnohpines 99 to the outer ends ci the passages lll i8 respectively in the dierentisl valve V.

electrical control devices comprise lrnlt it ies ll, en sutornetic return switch d manually operated switches H33, Mld. designsted Run," Cut 'teturnf Sten respectively. ne electrical control devices also include re lov E end R', operated ley solenoids El and econ controlling four circuits which ere simultaneously opened or closed. l also oro-A e double cole switch td@ adopted to he closed 'The @intersting ou;

control cuni, led

automat return ll he noted that the stop switch |05 is normally closed. while the out and return switches Mld end M35 are normally open, as are also the relny switches l-t und R' end the pump lay-poss control switch the machine on the cuttinfz which switch will reinsin closed until ricononened. "The cut switch lull is then closed crerctcr. This connects wire nigh the stop switch out switch the lower contacts o3? the limit lli, c lower switch element of relay switch l't, e. wire lili, the sole d S wires il@ end Mil to the line wire L'. ne solenoid 5 is thus enereicecl and the reley h ls thus raised and closes our l ts controlled thereby, ns shown, in i? upper switch elements lll and l elsy switch R connect the solenoid 'como control valve V to the line r thus energizing the solenoid 3G en" il e yslve tm to the position shown i nusilisry pump P' then supplies l. oscure through the pines t ond 3l .iorfe e piston 38 to the right, setting deliver oil through the to th shower the piston to the right for o breaching or out stroke.

As soon es the solenoid S has operated the relay switch R, the cut switch |04 may be released, es c. parallel holding circuit is then closed through the run switch |85, wires |23 and llt, e. switch element |25 of the relay switch R, and c wire litt. The holding circuit thus closed forms e shunt eround the out switch |84 and will hold the solenoid S energized after the cut switch is opened.

The remaining switch element |21 of the relay switch R closes s. circuit from the line wire L through a wire S28, the switch |21 and 9. wire t2@ to the solenoid S3 and line wire L. The double joole switch |08 is thus closed, energizing the solenoid 5t and moving the valve V3 to close ley-ness 55.

The breaching machine will now continue to onerste on its hro'echlng or cut stroke until the breaching heed M engages the double limit switch Mil i opening the lower contacts which con.u neet the i end i l, and closing the upper contscts 'which cre positioned in en sutornntlc return circuit to be described.

Assumimg that the automatic return switch |l2is open as shown ln the drawings, the opening of the lower contacts of the limit switch will break the circuit through the solenoid S, eillowing the relay switch R to move downward end onen the tour operating circuits controlled hy the switch elements lz, |2|, |25 and l2?. @nenen lne; of the switch elements |28 and lill glnes the solenoid 44, whereupon the punto control volvo -Vl returns to neutral position end the piston 38 returns to mid position, settine the pump P et neutral or 11o-discharge. 'When the switch |21 is opened, the solenoid ls deenergized, opening the switch |238 which the solenoid 58 end sllows the y- 'Mec relive V3 to own the ley-pass 55. The then in their originel position, except tl nl;

. contests of the limit sent-ch lill are now on i.

order to start the return stroke, the on r'- otcr the return. M5, which lnitldto.l e, series of similar operations to effect a return stroke. Closing of the switch |05 completes a circuit from the line wire L through the stop switch |06, a wire |30, limit switch |00, a. wire iti, the lower switch element |32 of the relay switch e. wire 93S, the solenoid S' and wires to the line wire L'.

The solenoid e' is thus energized, closing tour unifier circuits controlled thereby.

upper switch elements |40 and |45 connect, the line wires L and L through wires M2 fin-.l ld?, to energize the solenoid 45 and set the rmlve "lf2 in the return position shown in Fi". 3. 4@il under pressure is then supplied from the auxiliary pump P' through the pipes 5| and t2 to right-hond end o the pump control cylinder lll causing the piston 38 to move to the left and thereby setting the pump P to discharge through the pipe l to the chamber 2| connected to the righthsnd end of the main cylinder @il under pressure is thus delivered drt from the pump P through the tubular rod |6 tothe nis ton rod oeesefge l5. Because of the small cepscity of these ports, the piston and branching ld are returned at high speed to their idle or leit hond positions.

[is soon es the solenoid S' has -heen energie-ed. the return switch |05 may be opened, but o holdim' circuit will remain closed through the switch R'l to open. This ln turn breaks the circuit vthrough the solenoid 45 of the valve V2,

which then returns to neutral as shown in Fig. l, whereupon the pump P is also returned to neutral or rio-discharge position. Opening of the switch R' also breaks the circuit of the solenoid 68 and allows the valve V'-i to open the byepass 55. thus restoring all parts to the position shown-in Fig. i.

If it is desired to provide an automatic return stroke immediately following the working stroke, rather than lstopping the machine with the breaching head I4 in right-hand position. the

chargeof the pump P may be independently ad- .iusted for the cut and return strokes.

'I'he operation of the differential valve V in the tank T is as follows: The valve piston 10 isfreely slidable in the valve .cylinder 30, as each cylinder head is vented to prevent trapping of air or oil therein. The piston 10 will remain in any position in which it is set, untilpositively moved therefrom. When the machine is at rest, asshown in Fig. 1, the vent I valve 8| will open, permitting any air trapped in automatic return switch |02 (Fig. 2) will be closed.

As the -broaohlng head I4 then epproaohes lu;

right-hand limit of travel, it will open the lower contacts of the switch |0| as previously described, releasing the solenoid S, but at the same time by closing the upper contacts of theswitch 'lol it will complete a parallel or shunt circuitthrough a wire |50, the switch |02, a wire |5|, the

switch |0| and a wire |52 around the return switch |05. This will have the same effect as clos-4 .ing the return switch |05. and will automatically initiate a return stroke, instead oi stopping the machine with the head Il in right-hand position.

This method of operation is sometimes desirable where the work is of suena nature that it either end of the lmain cylinder l0 to escape by Adirect upward flow to the atmosphere. This is an important advantage, as it clears the cylinder of A air after each operation thereof.

The pipe 90 connected to the left-hand end of the differential valve is also connected to the pipe '4| leading to the left-hand end of the'pump control cylinder l0, and is thus under pressure when the machine is setvfor a broaching or cut stroke. At the same time. the pipe 9| is open to exhaust through the pipe 42,v valve V2 and return or exhaust pipe 52.

The valve piston 1l then moves to the-right-l I hand position shown in- Flg. 2, closing the connection 28 to the left-hand end of the cylinder i0 which is under pressure, and connecting the passage 25 throughzthe pipe 85 and back pressure valve 08 to the tank T which is at atmospheric pressure. As soon as pressure is developed in theA differential valve cylinder 20, the vent valve Il will automatically close'.

I thus provide for escape of surplus oil from the righthand end of the cylinder |0 andalso f arrange that this oil will escape only at a predetermined but reduced pressure, thus maintaincan be allowed to drop out oi the broalching flx- 'ture as'soon as the -broach is drawn therethrough and before the return stroke commences. No such automaticreversal is provided at the end ofthe the breach may be detached for insertion through a new piece of work.

' If it is desired to have the machine entirely under manual control as to starting and stopping in either direction, .the run switch |03 may be opened, in which event. the holding circuits are y disabled and the machine will run only so long as either the cut switch |04 or the return switch |05 is. held closed. This arrangement is convenient for jogging the broaching head in one direction or the other when setting 'up the machine.

The stopswitch |06 is not used in the'ordinary operation above described but is in the nature of an emergency switch,` which may be man,-

ually opened at any time and which will Vstop the machine at any point, regardless of whether the run switch |03 is open or closed and regard-7 less of the direction of movement of the broaching head.

It will be understood that the limit switches |00 and |0| are adjustable lengthwise of the -machine, so that the machine maybe operated with any desired length and locus of stroke.

Suitable stops may be provided to determine fthe operative position and discharge rate of the pump P- for both eutand return strokes. Such devices are indicated diagrammatically in Fig. 1 as adjustable stop screws |00 and ISI, engaged by a lug |62 associated with the rack bar 30. By

return stroke; as it is always necessary for a broaching machine to stop'at this point, sothat ing the desired back pressure in the right-hand portion of the main cylinder I0.

When the pump P is set for the return stroke, the pressures in the pipes 90 and 9| are reversed as indicated in Fig. 3. and the valve piston 1l isshifted to the left. The passage 26 is then' connected through the annular space 'll to the passage 20.- As only a relatively small amount of oil passes through the pump to the tubular rod '|I, the surplus oil in the left-hand end of the cylinder flows through the passages 28 and 2l to the right-hand end of the cylinder l0. On account of the small size of the fixed rod I6, as compared tothe piston rod |2, vthe oil thus bypassed from the left-hand end of the cylinder is not suicient to fill the right-hand end of the cylinder and such additional oil as is needed-will flow from the tank T through the vent valve 8| which is now open.

The differential valvethus important functions, In the first place, it vents Vthe main-cylinder and prevents the trapping of air therein. In the second place. it provides a desired back pressure against the piston during the working stroke. and in the third place it. provides the surplus oil required to fill the right-g hand end ofthe cylinder I0 during the return stroke.

- Particular 'attenuon lusl called to the im 'that the relay switches Rand R are both normally Kopen and that they remain'l closed only so long fas their respective solenoids S and 'B' are ener-- glued.A Accordingly, any failure of current in the line wires L and L will immediately cause these relay switches to open and the machine to stop in whatever position it. may chanceto oc- Oupy.

Also, any failure of current' in the circuits conadjusting the screws and IH, the rate of -dis- 75 trolling thesole'nold valve V will cause the valve l performs three to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

l. In a horizontal hydraulic breaching mau chine' havingl a main cylinder and piston, a

broachinghead actuated thereby and a normally-neutral, reversible-discharge pump for said cylinder, that improvement which comprises a hydraulic by-pass in parallel with said cylinder,

a-normally-open valve in said by-pass, a solenoid to close said valve, and, two electrical control circuits selectively closable to effect setting of said pump for cut and return strokes respectively, said solenoid being energized to close said by-pass valve by theclosing of either of said control circuits.

2. In a horizontal hydraulic breaching machine having a main cylinder 'and piston. a broaching head actuated thereby and a normallyneutral, reversible discharge pump for said cylinder, that improvement which comprises a hydraulic by-pass in parallel with said cylinder, a normally-open valve in said by-pass, a solenoid to' close said valve, two electrical control circuits selectively closable to eiect setting of said pump for cut and return strokes respectively, and holding means to maintain the selected circuit closed until the resultant stroke is completed. said:

solenoid being energized 4to close said by-pass valve by the closing lof either of said control circuits.

3. In a horizontal hydraulicl broaching machine having a main cylinder and piston, a` breaching head actuated thereby and a continu-- v ously operating reversible-discharge pump for said cylinder having a normal neutral no-discharge position, that improvement which comprises hydraulic means to shift said pump from neutral to discharge in either of two selective positions, spring means to .return said pump to' neutral, two electrical control circuits each closable manually to render said hydraulic means operative to overcome' said spring means and to shift said pump in a selected direction for s cut or return stroke', and electro-magnetic means to hold said electrical control circuit closeduntil the resultant stroke is completed, whereupon said spring means returns said pump to neutral.

4. Inv a horizontal hydraulic broaching machine'having a main cylinder and piston and a broaching head, in combination, a normallyneutral, reversible-discharge pump connected to said cylinder, electrically controlled hydraulic means to set and hold said pump for cut or return strokes of said broaching head, means to release said electrically controlled hydraulic means' at the end of each cut or return stroke, and a manually closable auxiliary circuit which,

, when inclosed condition, effects automatic reversal of pump discharge at the end of the out stroke, whereby the piston and broaching head are immediately and automatically started on a return stroke.

head actuatedl thereby, a normally-neutral, reversible-discharge pump connected to said cylinder, self-centering hydraulic pump-shifting mechanism, a self-centering valve for said hydraulic mechanism controlling the direction of discharge of said pump to said cylinder, manually controlled electrical means to shift said valve in a selectedl direction for out or return strokes, electrical devices to maintain said valve in shifted position until the end of the stroke, and automatic means to release said valve at the end o! the stroke.

6. In a horizontal hydraulic broaching machine, a main cylinder and piston, a broaching head actuated thereby, a normally-neutral, 'reversible-discharge pump connected to said cylinder, a self-centering valve controlling the direction of discharge of said pump to said cylinder.

manually controlled electrical means to shift said valve in a selected direction for cut or return strokes, devices to maintain said valve in shifted position until the end of the stroke, automatic means to release said valve at the end of the stroke, and additional optionally operative automatic means to cause said valve to be shifted immediately for a return stroke at the end of thecut stroke.

'1. In a horizontal hydraulic broaching machine having a main cylinder and piston, .a breaching head actuated thereby and a normallyneutral. reversible-discharge pump for said cylinder, that improvement which comprises hydraulic means to set said pump to actuate said 'piston and broaching head for cut and return strokes,

two electrical control circuits for said hydraulic means, manual means to close one circuit for a cut stroke, manual means to close the other circuit for a return stroke, a shunt circuit parallel to'said latter means, and optionally operative automatic means to close said shunt circuit and effect an immediate return stroke at the .end of a cutting stroke.

8. In a horizontal hydraulic broaching machine, a main cylinder and piston, a broaching head actuated thereby, a tank ,for surplus oil mounted above said cylinder, vn, differential piston .valve and cylinder'in said tank. connections from each end of said main cylinder to the valve cylinder, hydraulic means controlling the supply of V oil to said main cylinder, -and connections from said hydraulic means to said differential valve, said connectionsbeing effective to reverse the position of saidvalve each time the oil supply is shifted from one end to the other of said main cylinder.

9. In a horizontal hydraulic broaching machine, a main cylinder and piston, a breaching head actuated thereby, a tank tor surplus oil mounted above said cylinder, a differential piston valve and cylinder in said tank, connections from each end of said main cylinder to the valve cylinder, hydraulic means controlling the supply of oil to said main cylinder, connections `from said hydraulic means to said differential valve, said connections being effective to reverse the position of said valve as the oil supply is shifted from one end to the other of said main cylinder, and a normally-open vent valve between said valve cylinder and said tank, which vent valve 5. In a horizontal hydraulic broaching mais automatically closed by pressure above atmospheric in said valve cylinder.

l0. In a horizontal hydraulic ,broaching machine, a main cylinder andA piston, a breaching head actuated thereby, a tank for -surplus4 oil mounted above said cylinder. valve means in said tank eilective to transfer oil direct from the working end to the return end of said main cylinder during a return stroke, an automatic device to vent saidv valve means to atmosphere when neither end of the main cylinder is under pressure, and a back pressure device connected to said valve means and through which device surplus oil from the returnl side of the cylinder is discharged through said valve means to atmosphere at a predetermined reduced pressure during a Working stroke of said breaching machine.

ll. In a horizontal hydraulic broaching machine, a main cylinder and piston, a broaching head actuated thereby, a tank for surplus oil mounted above said cylinder, a differential valve submerged in oil in said tank and comprising a cylinder and piston, connections from each end of said main cylinder to the differential valve cylinder, a reversible discharge pump for said main cylinder, said piston being slidable in the differential valve cylinder and having piston rod draulic means to set said pump to actuate saidY piston and broachng head for cut and return strokes, two electrical control circuits for said hydraulic means, manual means to close one circuit for a cut stroke, manual means to close the other circuit for a return stroke, and a separate electrical holding connection parallel to each manual closing means and effective to hold its associated electrical circuit closed to the end of the stroke after the manual means is opened. KENNETH C. MONROE. 

